C𝐨𝐡𝐞𝐫𝐞𝐧𝐭 𝐋-𝐁𝐚𝐧𝐝 800𝐆 𝐙𝐑/𝐙𝐑+ 𝐏𝐥𝐮𝐠𝐠𝐚𝐛𝐥𝐞 𝐓𝐫𝐚𝐧𝐬𝐜𝐞𝐢𝐯𝐞𝐫𝐬 𝐟𝐫𝐨𝐦 𝐂𝐨𝐡𝐞𝐫𝐞𝐧𝐭

18 Sep C𝐨𝐡𝐞𝐫𝐞𝐧𝐭 𝐋-𝐁𝐚𝐧𝐝 800𝐆 𝐙𝐑/𝐙𝐑+ 𝐏𝐥𝐮𝐠𝐠𝐚𝐛𝐥𝐞 𝐓𝐫𝐚𝐧𝐬𝐜𝐞𝐢𝐯𝐞𝐫𝐬 𝐟𝐫𝐨𝐦 𝐂𝐨𝐡𝐞𝐫𝐞𝐧𝐭

On September 17, 2024, Coherent Corp. announced a groundbreaking development in optical networking with the release of the industry’s first L-band 800 Gbps coherent pluggable transceiver in a QSFP-DD form factor. This innovation is set to help increase fiber capacity and network scalability, particularly in hyperscale data centers and telecommunications infrastructure.

Expansion from C-band to L-band

Most systems operate predominantly in the C-band, a spectrum capable of supporting around 40 channels of the 800 Gbps system per fiber, or a total of 32 Tbps. By extending operations into the L-band, which has additional spectrum above the C-band, Coherent’s new transceivers can double fiber capacity from 32 Tbps to 64 Tbps by enabling 80 channels per fiber in the combined C and L-bands. This expansion is crucial for networks that are increasingly burdened by data-heavy applications such as cloud computing, video streaming, and the growing demand for 5G infrastructure.

QSFP-DD and 800G ZR/ZR+ Standards

The QSFP-DD (Quad Small Form Factor Pluggable – Double Density) is an advanced, compact form factor that allows network operators to upgrade and expand their network bandwidth without significantly increasing physical space requirements. Coherent’s 800G transceiver is fully 800G ZR/ZR+ compliant, a critical standard for high-speed, long-haul communications. 800G ZR and ZR+ are standards developed to support cost-effective, long-distance transmission over dense wavelength division multiplexing (DWDM) systems. The ZR standard focuses on shorter distances (up to 80 km), while ZR+ extends this to 120km, making them ideal for data center interconnects (DCI) and other telecom use cases.

By integrating coherent technology into this form factor, Coherent is also enabling higer data rate IP-over-DWDM (IPoDWDM) applications, which allow for direct router and switch connections to fiber optic networks without the need for external transponders. This innovation could reduce network costs by more than 400%, while also simplifying infrastructure by disaggregating the hardware involved.

Indium Phosphide Technology

At the heart of Coherent’s L-band transceiver is an Indium Phosphide (InP) modulator and receiver. This choice of material provides superior performance compared to alternatives like silicon photonics, which require additional amplification components, such as micro-EDFAs (Erbium-Doped Fiber Amplifiers), to achieve comparable transmission distances. The use of InP in the transceiver delivers higher power efficiency and cost-effectiveness, making it particularly advantageous in space-constrained environments like data centers.

Market Implications

The introduction of the 800G L-band transceiver is poised to have significant market impact. With bandwidth demand surging due to AI workloads, generative AI applications, and ubiquitous video streaming, operators are under immense pressure to increase network capacity. The adoption of L-band transmission technologies will likely accelerate, driven by the need for high-capacity, long-reach connections, especially in cloud networking and telecom backbones.

In fact, L-band reconfigurable optical add-drop multiplexers (ROADMs), which enable flexible routing of wavelengths across a network, have seen increased demand, nearly doubling in recent years. This trend is expected to continue as hyperscale data centers and large telecom operators integrate these high-speed transceivers to future-proof their networks.

Conclusion

Coherent’s L-band 800G transceiver represents a major leap forward in optical communications, offering a solution that meets the growing demands for bandwidth while simultaneously reducing costs and complexity. With its 800G ZR/ZR+ standard compliance and integration into the QSFP-DD form factor, the transceiver enables flexible, scalable, and efficient network expansion. This technology is set to play a crucial role in the next generation of high-performance optical networks, ensuring that data centers and telecom operators can keep pace with the ever-increasing global data demands.

Customer sampling for these transceivers will begin in the fourth quarter of 2024, with a full rollout expected shortly thereafter. Coherent’s innovative approach is likely to inspire similar developments across the industry, signaling an era of more efficient, cost-effective network expansion.

Learning more about coherent transceiver

To learn more about coherent transceivers, consider signing for our optical network training classes. In our advanced Certified Optical Network Engineer (CONE) course, we cover these impairments in great detail and explore solutions to mitigate them. Non-linear impairments are just one of the critical topics we address in this course, alongside other essential areas for optical network engineers. More importantly, you’ll gain the expertise needed to design high-performance networks using coherent detection technology.

However, to enroll in the CONE course, you must first complete the foundational Certified Optical Network Associate (CONA) course, which begins on October 14. If that date isn’t convenient, feel free to check our schedule for alternative dates. We also offer the option of delivering the training at your location for teams of 8 or more.

Jabulani Dhliwayo

Founder and Technical Director at FiberGuide, Lecturer, Scientist and Engineer. Passionate about optical networking and information and communication technologies. Connect with me on Linkedin – https://www.linkedin.com/in/jabulani-dhliwayo-1570b5b